Predicting lower limb periprosthetic joint infections: A review of risk factors and their classification

Effect of Multiantibiotic-Loaded Bone Cement on the Treatment of Periprosthetic Joint Infections of Hip and Knee Arthroplasties-A Single-Center Retrospective Study

BACKGROUND

Two-stage septic revision is the prevailing method for addressing late periprosthetic infections. Using at least dual-antibiotic-impregnated bone cement leads to synergistic effects with a more efficient elution of individual antibiotics. Recent data on the success rates of multiantibiotic cement spacers in two-stage revisions are rare.

METHODS

We conducted a retrospective follow-up single-center study involving 250 patients with late periprosthetic hip infections and 95 patients with prosthetic knee infections who underwent septic two-stage prosthesis revision surgery between 2017 and 2021. In accordance with the antibiotic susceptibility profile of the microorganisms, a specific mixture of antibiotics within the cement spacer was used, complemented by systemic antibiotic treatment. All patients underwent preoperative assessments and subsequent evaluations at 3, 6, 9, 12, 18, and 24 months post operation and at the most recent follow-up.

RESULTS

During the observation period, the survival rate after two-step septic revision was 90.7%. Although survival rates tended to be slightly lower for difficult-to-treat (DTT) microorganism, there was no difference between the pathogen groups (easy-to-treat (ETT) pathogens, methicillin-resistant staphylococci (MRS), and difficult-to-treat (DTT) pathogens). Furthermore, there were no differences between monomicrobial and polymicrobial infections. No difference in the survival rate was observed between patients with dual-antibiotic-loaded bone cement without an additional admixture (Copal® G+C and Copal® G+V) and patients with an additional admixture of antibiotics to proprietary cement.

CONCLUSION

Employing multiple antibiotics within spacer cement, tailored to pathogen susceptibility, appears to provide reproducibly favorable success rates, even in instances of infections with DTT pathogens and polymicrobial infections.

Polymeric Based Hydrogel Membranes for Biomedical Applications

The development of biomedical applications is a transdisciplinary field that in recent years has involved researchers from chemistry, pharmacy, medicine, biology, biophysics, and biomechanical engineering. The fabrication of biomedical devices requires the use of biocompatible materials that do not damage living tissues and have some biomechanical characteristics. The use of polymeric membranes, as materials meeting the above-mentioned requirements, has become increasingly popular in recent years, with outstanding results in tissue engineering, for regeneration and replenishment of tissues constituting internal organs, in wound healing dressings, and in the realization of systems for diagnosis and therapy, through the controlled release of active substances. The biomedical application of hydrogel membranes has had little uptake in the past due to the toxicity of cross-linking agents and to the existing limitations regarding gelation under physiological conditions, but now it is proving to be a very promising field This review presents the important technological innovations that the use of membrane hydrogels has promoted, enabling the resolution of recurrent clinical problems, such as post-transplant rejection crises, haemorrhagic crises due to the adhesion of proteins, bacteria, and platelets on biomedical devices in contact with blood, and poor compliance of patients undergoing long-term drug therapies.

Prevalence, Risk Factors and Microbiological Profile of Orthopaedic Surgical Site Infection in North-Eastern Peninsular Malaysia

Introduction

The devastating outcome of orthopaedic surgical site infections (SSI) are largely preventable if its risk factors, causative organisms and antimicrobial susceptibility patterns in the regional area are known.

Materials and methods

We conducted a retrospective study to address the lack of epidemiological and microbiological data on orthopaedic SSI in Malaysia. All the 80 patients diagnosed and treated for microbiologically proven orthopaedic SSIs in a tertiary hospital in Malaysia from April 2015 to March 2019 were included in a 1:2 case control study.

Results

The prevalence of SSI in clean and clean-contaminated surgeries was 1.243%, which is consistent with most of the studies worldwide, but is low compared to other studies done in Malaysia. The most common type of orthopaedics SSI were internal fixation infections (46.25%), superficial SSIs (25.2%) and Prosthetic joint infections (18.75%). Obesity and tobacco use were found to be significant risk factors of orthopaedic SSI. The most common perioperative prophylaxis used was IV cefuroxime. Majority of the cases (86.5%) received prolonged prophylactic antibiotics. The most common causative agent was Staphylococcus aureus (31.25%), followed by Pseudomonas aeruginosa (26.25%) and Enterobacter spp (7.5%). Methicillin-resistant Staphylococcus aureus (MRSA) accounted for 20% of the S. aureus infections. Up to 19.4% of the Gram-negative organisms are multidrug resistant. The higher rate of isolation of organisms resistant to the prophylactic antibiotics being used may be related to the prolonged use of prophylactic antibiotics, which exerted selective pressure for the acquisition of resistant organisms.

Conclusion

Despite its relatively low prevalence in our local institution and worldwide, the prevention of SSI in orthopaedic practice is crucial to avoid morbidity, mortality and high healthcare cost. This may be achieved by control of modifiable risk factors such as obesity and tobacco use, appropriate use of prophylactic antibiotics and implementation of good surgical and infection control practices.

Diabesity: a superadded effect contributing to worse total primary hip replacement operative outcomes for patients with diabetes and obesity

INTRODUCTION

Although the independent effects of diabetes mellitus and obesity on total hip replacement (THR) outcomes have been widely studied, their combined effect remains uncharacterised. This study aimed to assess the influence of diabesity on primary THR operative outcomes.

MATERIALS AND METHODS

A retrospective study was performed comparing the outcomes of patients with diabesity (diabetes mellitus and obesity [BMI ≥ 30]) with a control cohort after primary THR using an established arthroplasty database. Data were collected pre-operatively and 12 months post-operatively, including Oxford Hip Score (OHS), EuroQol 5-dimensions (EQ5D), post-operative satisfaction and complication rates.

RESULTS

2323 THRs were analysed, of which 94 (4%) had diabesity. Diabesity was independently associated with significantly worse OHS improvement post-operatively (- 1.85 points, 95% CI - 2.93 to - 0.76, p = 0.001). This reduction in addition to the independent effect of obesity (- 0.69 points, 95% CI - 1.18 to - 0.21, p = 0.005) resulted in an overall 2.54 point OHS reduction for patients with diabesity. Diabesity was not associated with EQ5D score change or post-operative satisfaction. Diabesity was independently associated with a worse pre-operative EQ5D score (-0.08 points, 95% CI -0.12 to -0.03, p = 0.002). When combining the associated risk of obesity (Odds Ratio (OR) 1.71, 95% CI 1.15-2.54, p = 0.008) with the superadded effect of diabesity (OR 2.37, 95% CI 1.19-4.71, p = 0.014) the rate of superficial wound infection post-operatively was significantly increased (OR 4.05, 95% CI 1.38-11.95). Obesity was associated with a significantly increased risk of deep infection (OR 3.67, 95% CI 1.55-8.68, p = 0.003), but no additive effect of diabetes was found.

CONCLUSIONS

Diabesity confers a superadded effect over established associations between THR outcomes and obesity and diabetes individually. Patients with diabesity experience worse improvement in hip-specific functional outcome, worse post-operative quality of life, and an increased risk of superficial and deep wound infection following THR.

Megaprostheses for the revision of infected hip arthroplasties with severe bone loss

Background

Periprosthetic hip infections with severe proximal femoral bone loss may require the use of limb salvage techniques, but no agreement exists in literature regarding the most effective treatment. Aim of this study is to analyze the infection eradication rate and implant survival at medium-term follow-up in patients treated with megaprostheses for periprosthetic hip infections with severe bone loss.

Methods

Twenty-one consecutive patients were retrospectively reviewed at a mean 64-month follow-up (24–120). Functional and pain scores, microbiological, radiological and intraoperative findings were registered. Kaplan Meier survival analysis and log rank test were used for infection free survival and implant survival analyses.

Results

The infection eradication rate was 90.5%, with an infection free survival of 95.2% at 2 years (95%CI 70.7–99.3) and 89.6%(95%CI 64.3–97.3) at 5 years. Only two patients required major implant revisions for aseptic implant loosening. The most frequent complication was dislocation (38.1%). The major revision-free survival of implants was 95.2% (95%CI 70.7–99.3) at 2 years and 89.6% (95%CI 64.3–97.3) at 5 years. The overall implant survival was 83.35% (CI95% 50.7–93.94) at 2 and 5 years. Subgroup analyses (cemented versus cementless MPs, coated versus uncoated MPs) revealed no significant differences at log rank test, but its reliability was limited by the small number of patients included.

Conclusions

Proximal femoral arthroplasty is useful to treat periprosthetic hip infections with severe bone loss, providing good functional results with high infection eradication rates and rare major revisions at medium-term follow-up. No conclusions can be drawn on the role of cement and coatings.

Prosthetic joint infections and legal disputes: a threat to the future of prosthetic orthopedics

Prosthetic joint infections (PJI) represent one of the major problems in orthopedic prosthetic surgery. The incidence of PJIs varies according to the site of intervention, and different published case studies report occurrence at 0.5 to 3.0% in the event of first implants, with a significant greater risk in the case of prosthesis revisions. The diagnosis of prosthetic infections is seldom simple, needing a multi-specialist approach, which includes the accurate collection of patient anamnesis, its clinical evaluation, the evaluation of inflammation biomarkers, and the use of imaging techniques. It is essential to identify the bacteria responsible for the infection not only for an accurate diagnosis, but also to select the correct antibiotic treatment. Failure to identify the bacteria involved makes it impossible to establish targeted systemic antibiotic therapy. In developed countries such as Italy, the right to health is guaranteed by the Constitution, where the institutions that provide health services must be staffed by a team of medical professionals that can guarantee the safest possible health pathways. Risk management represents the set of actions aimed at improving the quality of the care provided, the adherence to guidelines and good care practices with the final objective of guaranteeing patients' safety. All hospitals, including the ones where prosthetic orthopedic surgery is performed, must adopt clinical risk management procedures which, through prospective tools aimed at preventing errors and complications and by retrospective methods, permit the identification of critical points in the different phases of the process and propose actions for improvement. The constant increase in litigation for malpractice in Western countries, especially in Italy, calls for special attention to the problem of PJIs and the in-depth assessment of medico-legal problems, also considering the new legislative initiatives in the field of medical malpractice. Hospitals need to tackle the onset of PJIs in a transparent and linear fashion by constantly informing the patient on their progress.

Fatal Clostridium Infection in a Leg-Amputated Patient after Unsuccessful Knee Arthroplasty

Prosthetic joint infection (PJI) is a possible complication occurring after prosthesis implantation. We describe the case of a patient with early postoperative multidrug-resistant polymicrobial PJI and mixed infection of the surgical wound. Despite the removal of the prosthesis, the positioning of double-stage exchange, and dehiscence debridement of the surgical wound, the infection continued. Positioning of an external fixator, plastic reconstruction with a skin graft, and continuous (two years) multiple antimicrobial therapy led to the resolution of the knee infection; a knee prosthesis was implanted, but a new infection of the extensus apparatus by multidrug-resistant Klebsiella pnumoniae followed. It was complicated by surgical wound dehiscence, forcing us to remove the prosthesis, put a new external fixator, and continue with the antibiotic treatment, with no results, and, finally, proceed to a leg amputation. Fourteen days after, the patient was discharged in good clinical condition but, fifteen days later, during rehabilitation in another hospital, the patient developed a severe Clostridium difficilis infection with profuse, intense diarrhea, toxic megacolon, and septic shock; despite colectomy and treatment in an intensive care unit, he died four months later. Patients affected by polymicrobial PJI are at high risk of treatment failure and, therefore, should be given a warning, in good time and appropriate form, of the likelihood of leg amputation.

The AAHKS Clinical Research Award: Extended Oral Antibiotics Prevent Periprosthetic Joint Infection in High-Risk Cases: 3855 Patients With 1-Year Follow-Up

BACKGROUND

Surgical and host factors predispose patients to periprosthetic joint infection (PJI) after primary total hip arthroplasty (THA) and total knee arthroplasty (TKA). While surgical factors are modifiable, host factors can be challenging, and there are limited data demonstrating that preoperative patient optimization decreases risk of PJI. The goal of this study was to evaluate whether extended oral antibiotic prophylaxis reduces the one-year infection rate in high-risk patients.

METHODS

A total of 3855 consecutive primary THAs and TKAs performed between 2011 and 2019 at a suburban academic hospital with modern perioperative and infection-prevention protocols were retrospectively reviewed. Beginning in January 2015, a 7-day oral antibiotic prophylaxis protocol was implemented after discharge for patients at high risk for PJI. The percentage of high-risk patients diagnosed with PJI within 1 year was compared between groups that did and did not receive extended antibiotic prophylaxis. Univariate and logistic regression analyses were performed, with P ≤ .05 denoting statistical significance.

RESULTS

Overall 1-year infection rates were 2.26% and 0.85% after THA and TKA, respectively. High-risk patients with extended antibiotic prophylaxis had a significantly lower rate of PJI than high-risk patients without extended antibiotic prophylaxis (0.89% vs 2.64%, respectively; P < .001). There was no difference in the infection rate between high-risk patients who received antibiotics and low-risk patients (0.89% vs 1.29%, respectively; P = .348) with numbers available.

CONCLUSION

Extended postoperative oral antibiotic prophylaxis for 7 days led to a statistically significant and clinically meaningful reduction in 1-year infection rates of patients at high risk for infection. In fact, the PJI rate in high-risk patients who received antibiotics was less than the rate seen in low-risk patients. Thus, extended oral antibiotic prophylaxis may be a simple measure to effectively counteract poor host factors. Moreover, the findings of this study may mitigate the incentive to select healthier patients in outcome-based reimbursement models. Further study with a multicenter randomized control trial is needed to further validate this protocol.

LEVEL OF EVIDENCE

Therapeutic level III.

Prosthetic joint infection. A relevant public health issue

Prosthetic joint infection (PJI) is a common complication of the knee and hip arthroplasty and represents a huge challenge for physicians. PJI raises serious social, economic and clinical concerns in the public health that need a comprehensive approach to better focus on proven strategies for disease prevention and treatment. History and clinical signs on joint site are useful means for suspecting PJI that need to be confirmed through major and minor diagnostic criteria. The pathogen isolation and the resulting antibiogram are crucial to guide the correct antibiotic strategy and together with surgical treatment (prosthesis revision and spacer implantation) represent the cornerstones to eradicate the infection before attempting a new arthroplasty. External fixator with removal of the spacer may be an option before performing a new arthroplasty when the infection does not heal. Arthrodesis may also be considered if the arthroplasty is contraindicated. Limb amputation is the last chance when pathogen eradication failed and might lead to life-threatening situations.

Risk factors for periprosthetic joint infection following total ankle replacement

BACKGROUND

Identifying preoperative patient characteristics that correlate with an increased risk of periprosthetic joint infection (PJI) following total ankle replacement (TAR) is of great interest to orthopaedic surgeons, as this may assist with appropriate patient selection. The purpose of this study is to systematically review the literature to identify risk factors that are associated with PJI following TAR.

METHODS

Utilizing the terms "(risk factor OR risk OR risks) AND (infection OR infected) AND (ankle replacement OR ankle arthroplasty)" we searched the PubMed/MEDLINE electronic databases. The quality of the included studies was then assessed using the AAOS Clinical Practice Guideline and Systematic Review Methodology. Recommendations were made using the overall strength of evidence.

RESULTS

Eight studies met the inclusion criteria. A limited strength of recommendation can be made that the following preoperative patient characteristics correlate with an increased risk of PJI following TAR: inflammatory arthritis, prior ankle surgery, age less than 65 years, body mass index less than 19, peripheral vascular disease, chronic lung disease, hypothyroidism, and low preoperative AOFAS hindfoot scores. There is conflicting evidence in the literature regarding the effect of obesity, tobacco use, diabetes, and duration of surgery.

CONCLUSIONS

Several risk factors were identified as having an association with PJI following TAR. These factors may alert surgeons that a higher rate of PJI is possible. However, because of the low level of evidence of reported studies, only a limited strength of recommendation can be ascribed to regard these as risk factors for PJI at this time.

Time-dependent surgical instrument contamination begins earlier in the uncovered table than in the covered table

PURPOSE

Time-dependent surgical instrument contamination and the effect of covering during arthroplasty have not been investigated. This study aimed to evaluate time-dependent contamination of surgical instruments and the effect of covering on contamination as well as to perform bacterial typing of contaminated samples. The hypothesis was that covering the surgical instruments would decrease contamination rates.

METHODS

Sixty patients who underwent total knee arthroplasty were randomized and divided into two groups: surgical instruments covered with a sterile towel or surgical instruments left uncovered. K-wires were used to extract microbiological samples. The K-wires were placed in a liquid culture medium at 0, 15, 30, 60, 90, and 120 min. After 24-h incubation period, samples from liquid cultures were cultured on blood agar using swabs. Samples with growth after 48 h were considered contaminated. Microscopic, staining, and biochemical properties were used for bacterial typing.

RESULTS

Bacterial growth started after 30 and 60 min in the uncovered and covered groups, respectively. An increase in the number of K-wires contaminated with time was detected. At least 10,000 CFU/mL bacterial load was observed in the culture samples. Contamination was more significant in the uncovered group. A statistically significant difference in contamination was found between the uncovered and covered groups at 30-, 60-, 90-, and 120 min (p = 0.035, p = 0.012, p = 0.024, and p = 0.037, respectively). The most common bacteria on the contaminated instruments were coagulase-negative Staphylococci (60.4%), Staphylococcus aureus (22.9%), and Streptococcus agalactia (16.7%), respectively.

CONCLUSION

The risk of contamination increases with time. However, it may decrease if surgical instruments are covered. In the clinical practice, empiric antibiotic regimens based on the type of identified microorganisms in this study may be developed for postoperative periprosthetic joint infection prophylaxis.

LEVEL OF EVIDENCE

Prognostic, Level II.

Risk factors for chronic biofilm-related infection associated with implanted medical devices

BACKGROUND

The use of implanted medical devices is associated with a small but clinically important risk of foreign body infection. A key question is: why do some patients develop chronic infection associated with an implanted device, but most do not?

AIMS

The literature on patient-specific risk factors for chronic infections associated with five types of implants was surveyed to glean clues about the etiology of these infections.

SOURCES

Data were collected from 47 articles through calendar year 2017 for five categories of device-related infections: cardiovascular implantable electronic devices (CIEDs), hernia meshes, prosthetic hip and knee joints, prosthetic shoulder joints and breast implants.

CONTENT

Important risk factors include immunomodulation/steroid therapy, diabetes, smoking, and renal disease/haemodialysis-findings that point to a critical role of a compromised innate immune response in determining vulnerable subpopulations.

IMPLICATIONS

A model of biofilm-related device infection is presented that posits defects in the innate immune response both systemically and locally, in the immediate vicinity of an abiotic biomaterial. The limitations of in vitro and animal models of chronic device-related infections are discussed in this context as are implications for research and clinical practice.

Factors associated with infection of primary total knee prosthesis in older adults in a referral hospital in Peru. 2012-2015

OBJECTIVE

To determine the risk factors associated with prosthetic knee infection in elderly patients in a referral hospital in Peru.

PATIENTS AND METHODS

A case and control study was performed. The calculated sample was 44 cases and 132 controls. The data were collected retrospectively from clinical records. U-Mann Whitney and Chi-square tests were performed in the comparison of cases and controls. Odds ratios (OR) were calculated in a binary logistic regression analysis to identify the risk factors, a P<.05 and a 95% confidence interval (CI) were considered significant.

RESULTS

Significant (P<.05) risk factors evidenced in the bivariate analysis were obesity (OR=9.72; 95%CI: 4.47-21.14), smoking (OR=4.06; 95%CI: 1.59-10.39), rheumatoid arthritis (OR=4.66; 95%CI: 1.52-14.32), diabetes mellitus type2 (OR=5.63; 95%CI: 2.69-11.78), persistent drainage (OR=9.27; 95%CI: 3.85-22.31), superficial infection (OR=6.87; 95%CI: 3.25-14.49) and prolonged hospital stay (OR=4.67; 95%CI: 2.26-9.64). In the multivariate analysis where it was adjusted for confounding variables, it was determined that risk factors were obesity (ORa=9.14; 95%CI: 3.28-25.48), diabetes mellitus (ORa=3.77; 95%CI: 1.38-10.32), persistent drainage (ORa=4.64; 95%CI: 1.03-20.80) and superficial wound infection (ORa=27.35; 95%CI: 2.57-290.64).

CONCLUSIONS

Risk factors for prosthetic knee infection identified in this study are preventable. The main risk factors were obesity, diabetes mellitus type2, superficial wound infection and persistent drainage, which were considered together or separately to be risk factors in the population studied.

Establishing a patient centered, outpatient total joint home recovery program within an integrated healthcare system

Outpatient total joint home recovery (HR) is a rapidly growing initiative being developed and employed at high volume orthopedic centers. Minimally invasive surgery, improved pain control and home health services have made HR possible. Multidisciplinary teams with members ranging from surgeons and anesthesiologists to hospital administrators, physical therapists, nurses and research analysts are necessary for success. Eligibility criteria for outpatient total joint arthroplasty will vary between medical centers. Surgeon preference in addition to medical comorbidities, social support, preoperative patient mobility and safety of the HR location are all factors to consider when selecting patients for outpatient total joint HR. As additional knowledge is gained, the next steps will be to establish 'best practices' and speciality society-endorsed guidelines for patients undergoing outpatient total joint arthroplasty.

Antibiotic-impregnated bone cement for preventing infection in patients receiving primary total hip and knee arthroplasty: A meta-analysis

BACKGROUND

Surgical-site infections after primary total joint arthroplasty (TJA) are a significant issue. Antibiotic-impregnated bone cement (AIBC) has been widely used for the treatment of infected joints, but routine use of AIBC in primary TJA remains controversial. In this systematic review, we evaluated the efficacy of AIBC in reducing surgical-site infections after primary TJA.

METHODS

We systematically searched Pubmed, EMbase, Cochrane Library, CMB, CNKI, and WanFang Data for studies (published until June 1, 2019) evaluating AIBC use in reducing infection rates. Two reviewers independently screened the literature according to inclusion and exclusion criteria, extracted data, and assessed the methodological quality of included studies. Meta-analysis was performed using Review Manager 5.3 software. The registration number is CRD42017078341 in PROSPERO.

RESULTS

In total, 10 studies were included, resulting in a sample size of 13,909 arthroplasty cases. The overall pooled data demonstrated that, compared with systemic antibiotics, AIBC was more effective in decreasing deep infection rates (odds ratio [OR] = 0.35, 95% confidence interval [CI] = 0.14-0.89, P = .030), although there were higher superficial infection rates with AIBC (OR = 1.53, 95% CI = 1.11-2.11, P = .010). Compared to systemic antibiotics alone, AIBC with systemic antibiotics significantly decreased deep infection rates (OR = 0.55, 95% CI = 0.41-0.75, P = .0001) but there was no difference in superficial infection rates (OR = 1.43, 95% CI = 0.81-2.54, P = .220). In the subgroup analysis, both randomized controlled trials and cohort studies had reduced deep infection rates after primary TJA (OR = 0.61, 95% CI = 0.37-0.99, P = .050 and OR = 0.49, 95% CI = 0.34-0.70, P = .0001, respectively). AIBC decreased deep infection rates in both total hip and knee arthroplasty (OR = 0.25, 95% CI = 0.12-0.52, P = .0002 and OR = 0.62, 95% CI = 0.45-0.87, P = .005, respectively). Deep infection rates were significantly decreased by AIBC with gentamicin (OR = 0.31, 95% CI = 0.20-0.49, P < .00001) but unaffected by AIBC with cefuroxime (OR = 0.35, 95% CI = 0.10-1.20, P = .100). Deep infection rates in the AIBC and control groups were similar when laminar airflow was applied to the operating room (OR = 0.90, 95% CI = 0.60-1.35, P = .620); however, without laminar airflow, the efficacy of AIBC in decreasing deep infection rates was significantly higher than that of control group (OR = 0.21, 95% CI = 0.08-0.59, P = .003).

CONCLUSIONS

AIBC may significantly decrease deep infection rates after primary total hip and knee arthroplasty, with or without systemic antibiotics.

Active remote-site musculoskeletal infection as a risk factor for periprosthetic infection in a new joint implant: A case series

Introduction

Arthroplasty has always been associated with complications, such as the possibility of periprosthetic infection. The presence of an active infection at the site of the planned surgery is considered a contraindication for the new implant. However, it is unclear whether there is an association between the presence of remote musculoskeletal infection and the development of infection in the prosthetic joint itself. We report six cases involving patients with active ongoing musculoskeletal infections at a remote site who underwent arthroplasty.

Presentation of cases

Four male and two female patients were included in this review. Three patients underwent total hip arthroplasty, one underwent hip hemiarthroplasty, and two underwent total knee arthroplasty. All surgeries were performed in the presence of different stages of infection at a remote site; two had active infections with pus-discharging sinus, one was being treated with long-term oral antibiotic suppression, and three patients were diagnosed with remote prosthetic joint infections on the basis of joint aspiration or intraoperative cultures. Clinical assessments of pain, wound erythema or drainage, and soft tissue swelling were performed at follow-up. Radiography and analysis of inflammatory marker levels were performed preoperatively and 6 weeks postoperatively.

Discussion

All six patients were followed-up for at least 18 months (mean, 4.6 years; range, 18 months to 9 years). No evidence of superficial surgical-site infection or deep prosthetic joint infection was observed.

Conclusion

The presence of an active infection at a remote site might not be a contributing factor to periprosthetic joint infection.

•

Six patients underwent arthroplasty in presence of active remote-site infections.

•

No evidence of superficial surgical-site infection was seen (18-month follow-up).

•

No evidence of deep prosthetic joint infection was observed (18-month follow-up).

•

Active remote-site infection is not associated with periprosthetic joint infection.

The World Association against Infection in Orthopaedics and Trauma (WAIOT) procedures for Microbiological Sampling and Processing for Periprosthetic Joint Infections (PJIs) and other Implant-Related Infections

While implant-related infections continue to play a relevant role in failure of implantable biomaterials in orthopaedic and trauma there is a lack of standardised microbiological procedures to identify the pathogen(s). The microbiological diagnosis of implant-related infections is challenging due to the following factors: the presence of bacterial biofilm(s), often associated with slow-growing microorganisms, low bacterial loads, previous antibiotic treatments and, possible intra-operative contamination. Therefore, diagnosis requires a specific set of procedures. Based on the Guidelines of the Italian Association of the Clinical Microbiologists (AMCLI), the World Association against Infection in Orthopaedics and Trauma has drafted the present document. This document includes guidance on the basic principles for sampling and processing for implant-related infections based on the most relevant literature. These procedures outline the main microbiological approaches, including sampling and processing methodologies for diagnostic assessment and confirmation of implant-related infections. Biofilm dislodgement techniques, incubation time and the role of molecular approaches are addressed in specific sections. The aim of this paper is to ensure a standardised approach to the main microbiological methods for implant-related infections, as well as to promote multidisciplinary collaboration between clinicians and microbiologists.

Risk factors associated with revision for prosthetic joint infection following knee replacement: an observational cohort study from England and Wales

Background

Prosthetic joint infection is a devastating complication of knee replacement. The risk of developing a prosthetic joint infection is affected by patient, surgical, and health-care system factors. Existing evidence is limited by heterogeneity in populations studied, short follow-up, inadequate power, and does not differentiate early prosthetic joint infection, most likely related to the intervention, from late infection, more likely to occur due to haematogenous bacterial spread. We aimed to assess the overall and time-specific associations of these factors with the risk of revision due to prosthetic joint infection following primary knee replacement.

Methods

In this cohort study, we analysed primary knee replacements done between 2003 and 2013 in England and Wales and the procedures subsequently revised for prosthetic joint infection between 2003 and 2014. Data were obtained from the National Joint Registry linked to the Hospital Episode Statistics data in England and the Patient Episode Database for Wales. Each primary replacement was followed for a minimum of 12 months until the end of the observation period (Dec 31, 2014) or until the date of revision for prosthetic joint infection, revision for another indication, or death (whichever occurred first). We analysed the data using Poisson and piecewise exponential multilevel models to assess the associations between patient, surgical, and health-care system factors and risk of revision for prosthetic joint infection.

Findings

Of 679 010 primary knee replacements done between 2003 and 2013 in England and Wales, 3659 were subsequently revised for an indication of prosthetic joint infection between 2003 and 2014, after a median follow-up of 4·6 years (IQR 2·6–6·9). Male sex (rate ratio [RR] for male vs female patients 1·8 [95% CI 1·7–2·0]), younger age (RR for age ≥80 years vs <60 years 0·5 [0·4–0·6]), higher American Society of Anaesthesiologists [ASA] grade (RR for ASA grade 3–5 vs 1, 1·8 [1·6–2·1]), elevated body-mass index (BMI; RR for BMI ≥30 kg/m²vs <25 kg/m² 1·5 [1·3–1·6]), chronic pulmonary disease (RR 1·2 [1·1–1·3]), diabetes (RR 1·4 [1·2–1·5]), liver disease (RR 2·2 [1·6–2·9]), connective tissue and rheumatic diseases (RR 1·5 [1·3–1·7]), peripheral vascular disease (RR 1·4 [1·1–1·7]), surgery for trauma (RR 1·9 [1·4–2·6]), previous septic arthritis (RR 4·9 [2·7–7·6]) or inflammatory arthropathy (RR 1·4 [1·2–1·7]), operation under general anaesthesia (RR 1·1 [1·0–1·2]), requirement for tibial bone graft (RR 2·0 [1·3–2·7]), use of posterior stabilised fixed bearing prostheses (RR for posterior stabilised fixed bearing prostheses vs unconstrained fixed bearing prostheses 1·4 [1·3–1·5]) or constrained condylar prostheses (3·5 [2·5–4·7]) were associated with a higher risk of revision for prosthetic joint infection. However, uncemented total, patellofemoral, or unicondylar knee replacement (RR for uncemented vs cemented total knee replacement 0·7 [95% CI 0·6–0·8], RR for patellofemoral vs cemented total knee replacement 0·3 [0·2–0·5], and RR for unicondylar vs cemented total knee replacement 0·5 [0·5–0·6]) were associated with lower risk of revision for prosthetic joint infection. Most of these factors had time-specific effects, depending on the time period post-surgery.

Interpretation

We have identified several risk factors for revision for prosthetic joint infection following knee replacement. Some of these factors are modifiable, and the use of targeted interventions or strategies could lead to a reduced risk of revision for prosthetic joint infection. Non-modifiable factors and the time-specific nature of the effects we have observed will allow clinicians to appropriately counsel patients preoperatively and tailor follow-up regimens.

Funding

National Institute for Health Research.

The prevention of infection: 12 modifiable risk factors

AIMS

Prosthetic joint infection (PJI) remains a serious complication that is associated with high morbidity and costs. The aim of this study was to prepare a systematic review to examine patient-related and perioperative risk factors that can be modified in an attempt to reduce the rate of PJI.

MATERIALS AND METHODS

A search of PubMed and MEDLINE was conducted for articles published between January 1990 and February 2018 with a combination of search terms to identify studies that dealt with modifiable risk factors for reducing the rate of PJI. An evidence-based review was performed on 12 specific risk factors: glycaemic control, obesity, malnutrition, smoking, vitamin D levels, preoperative Staphylococcus aureus screening, the management of anti-rheumatic medication, perioperative antibiotic prophylaxis, presurgical skin preparation, the operating room environment, irrigant options, and anticoagulation.

RESULTS

Poor glycaemic control, obesity, malnutrition, and smoking are all associated with increased rates of PJI. Vitamin D replacement has been shown in preliminary animal studies to decrease rates of PJI. Preoperative Staphylococcus aureus screening and appropriate treatment results in decreased rates of PJI. Perioperative variables, such as timely and appropriate dosage of prophylactic antibiotics, skin preparation with chlorohexidine-based solution, and irrigation with dilute betadine at the conclusion of the operation, have all been associated with reduced rates of PJI. Similarly, aggressive anticoagulation and increased operating room traffic should be avoided to help minimize risk of PJI.

CONCLUSION

PJI remains a serious complication of arthroplasty. Surgeons should be vigilant of the modifiable risk factors that can be addressed in an attempt to reduce the risk of PJI.

Two-stage revision for the culture-negative infected total hip arthroplasty : A comparative study

Aims

Periprosthetic joint infection (PJI) remains a challenging complication following total hip arthroplasty (THA). It is associated with high levels of morbidity, mortality and expense. Guidelines and protocols exist for the management of culture-positive patients. Managing culture-negative patients with a PJI poses a greater challenge to surgeons and the wider multidisciplinary team as clear guidance is lacking.

Patients and Methods

We aimed to compare the outcomes of treatment for 50 consecutive culture-negative and 50 consecutive culture-positive patients who underwent two-stage revision THA for chronic infection with a minimum follow-up of five years.

Results

There was no significant difference in the outcomes between the two groups of patients, with a similar rate of re-infection of 6%, five years post-operatively. Culture-negative PJIs were associated with older age, smoking, referral from elsewhere and pre-operative antibiotic treatment. The samples in the culture-negative patients were negative before the first stage (aspiration), during the first-stage (implant removal) and second-stage procedures (re-implantation).

Conclusion

Adherence to strict protocols for selecting and treating culture-negative patients with a PJI using the same two-stage revision approach that we employ for complex culture-positive PJIs is important in order to achieve control of the infection in this difficult group of patients.

Cite this article: Bone Joint J 2018;(1 Supple A)100-B:3–8.

Chronic kidney disease is associated with a risk of higher mortality following total knee arthroplasty in diabetic patients: a nationwide population-based study

Diabetes and chronic kidney disease (CKD) are associated with a higher rate of complications in patients undergoing total knee arthroplasty (TKA). The purpose of this study was to determine the effects of CKD and diabetes in patients after TKA. Diabetic patients who received unilateral primary TKA between January 2008 and December 2011 were enrolled. The follow-up period was more than 6 months. The primary outcome was a TKA-related infection and the secondary outcome was all-cause mortality. The study cohort included 13844 patients who were followed for a mean period of 2 years, of whom 1459 (10.5%) had CKD. The patients with CKD were older than those without CKD (71.6 versus 70.3 years, P<0.0001) and had higher rates of hypertension, gouty arthritis, ischemic heart disease, chronic pulmonary obstructive disease, pulmonary embolism and deep vein thrombosis (all P<0.0001). After adjustment of comorbidities, the CKD group had a higher incidence of urinary tract infections (OR: 1.61, 95% CI: 1.19-2.17). There were no significant differences in wound infections, pneumonia, pulmonary embolism or in-hospital death between the two groups. After adjustment of confounders, the CKD group had higher rates of myocardial infarction (HR: 2.06, 95% CI: 1.26–3.39) and mortality (HR: 1.99, 95% CI: 1.59–2.48). The risk of TKA-related infection during follow-up was comparable between the two groups (HR: 1.31, 95% CI: 0.94–1.82). In conclusion, CKD is associated with increased risks of urinary tract infections, myocardial infarction and all-cause mortality after TKA. Surgeons should be aware of this when evaluating TKA patients with renal disease.